Upper straight rod and lower expanded-base structure cast-in-place pile capable of reducing negative frictional resistance and construction method thereof

Abstract

The invention discloses an upper straight rod and lower expanded-base structure cast-in-place pile capable of reducing negative frictional resistance and a construction method thereof. The upper straight rod and lower expanded-base structure cast-in-place pile comprises a cast-in-place concrete pile, prestressed reinforcements located in the cast-in-place concrete pile, a pile body outer sleeve located outside the cast-in-place concrete pile and a bearing platform arranged at the upper end of the cast-in-place concrete pile; the cast-in-place concrete pile is formed by directly connecting an upper straight rod section and a lower expanded-base section, and the prestressed reinforcements and the cast-in-place concrete pile are coaxially arranged to form the upper straight rod and lower expanded-base structure cast-in-place concrete pile; the outer wall of the straight rod part of the cast-in-place concrete pile is sleeved with the pile body outer sleeve; and the pile body outer casing pipe comprises an inner layer casing pipe and an outer layer casing pipe, and joints, exceeding the pile top of the cast-in-place concrete pile, of the prestressed reinforcements are reserved to be connected with the bearing platform. The method has a good effect of reducing the negative friction under the geological conditions of high-compressibility soil layers such as soft soil, collapsible loess and dredger fill.

Description

technical field [0001] The invention belongs to the technical field of buildings, and in particular relates to a cast-in-place pile with an upper straight bar and a lower expanded bottom structure for reducing negative friction resistance and a construction method thereof. Background technique [0002] As pile foundations are more and more widely used in engineering, some new problems, such as pile foundation negative friction, also appear. The vertical load on the top of piles such as buildings (structures) is mainly borne by the pile side friction resistance and pile tip resistance. Among them, the pile side friction resistance is formed due to the settlement of the pile side soil, and the pile tip resistance is provided by the pile tip bearing layer. . Generally speaking, the settlement of the soil around the pile is smaller than that of the pile, that is, the pile moves downward relative to the soil. At this moment, the direction of frictional resistance generated by th...

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Problems solved by technology

[0003] Negative frictional resistance will cause additional settlement of friction piles. When a part of the foundation of a building or some piles in the same foundation has a large negative frictional resistance, it will cause uneven settlement of the pile group, and the superstructure will be damaged. The beauty of the building or the use of the function, the severe case will cause a series of engineering accidents; the negative friction resistance will increase the load of the pile body of the end-bearing pile, so that the strength of the pile body or the bearing layer at the pile end will be destroyed

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